Principles - Upper GI System Flashcards
What is the upper GI tract?
Oral cavity Oropharynx Laryngopharynx Oesophagus Stomach Small Intestines
Where does jaw opening and closing occur?
At the right and left TMJs (temporomandibular joints)
Synovial joints between mandibular fossa and articular tubercle of the temporal bone and the head of the condylar process of the mandible
What are the muscles of mastication?
Masseter
Temporalis
medial pterygoid
lateral pterygoid
Which muscle prevents dribbling?
The orbicularis oris
Circularly arranged around the lips - contraction draws the lips together
Where are the upper/lower dental arches contained?
Upper - maxilla
Lower - mandible
What is the correct name for the gums?
Gingivae
Which areas of the oral cavity have surface keratin?
Gingivae and hard palate - for their protection during chewing
Describe the mucosa of the oral cavity.
Covered with stratified squamous epithelium
What bones make up the hard palate?
The maxilla and the palatine bone
What are the features associated with the soft palate?
Palatine tonsil - sits between the arches of the soft palate
Uvula - 2 of the soft palate muscles sit within this, hangs down at the back of the oral cavity
What is the special sensation of the oral cavity?
Taste
What are papillae? What are their different functions?
Finger-like structures on the dorsum of the tongue
Some give the surface texture and help the tongue manipulate food
Others are concerned with taste
Where/what is the posterior 1/3rd of the tongue?
The vertical part of the tongue
Not in the oral cavity - in the oropharynx
What papilla have taste buds?
Foliate papillae (most posterior)
Vallate papillae
Fungiform papillae
What papilla don’t have taste buds?
Filiform papillae (most anterior)
How is the tongue suspended in the oral cavity?
There are 4 pairs of extrinsic muscles of the tongue
Originate external to the tongue and insert into it
Move the tongue around during mastication, speech and swallowing
How is the shape of the tongue modified?
There are 4 pairs of skeletal intrinsic muscles of the tongue
Modify the shape of the tongue during function e.g. rolling
What is the buccinator? What does it do?
This is the muscle of the cheeks
With the help of the tongue, the buccinator acts to position the food bolus between the occlusal surfaces of the teeth for mastication
How many teeth should there be in the adult mouth?
32
What is the occlusion?
The bite
How the occlusal/biting surfaces of the upper and lower teeth fit together
What does saliva contain?
99% water
Mucin (lubricant) - aids swallowing and speech, keeps mucosa moist, buffer for plaque acids and also contains antimicrobial elements and amylase to begin CHO digestion
What are the major salivary glands?
Parotid - near the ear
Submandibular - under the mandible
Sublingual - under the tongue
What are the minor salivary glands for?
Basal secretion - background and continuous secretion of saliva to keep the mouth moist
Where do the salivary glands empty?
Parotid duct - inner surface of the cheek, usually opposite the maxillary second molar
Sublingual duct - under the tongue
Submandibular duct - the floor of mouth on both sides of the tongue frenulum at sublingual caruncula
What is the pharynx?
The throat
A muscular ‘incomplete tube’ lined with non-keratinised stratified squamous epithelium
Tonsils are contained here
What are the three parts of the pharynx?
Nasopharynx - posterior to nasal cavities
Oropharynx - posterior to oral cavity
Laryngopharynx - posterior to larynx, in-between epiglottis and oesophagus
What is Waldeyer’s ring?
Ring of tonsils
Arrangement of tonsils in the pharynx
What do the uvula and epiglottis do together?
Guide the food bolus away from the midline laryngeal inlet, so food isn’t aspirated
What/where are the longitudinal muscles of the pharynx?
Inner vertically arranged layer
Attach inferiorly to the larynx
contract during swallowing to shorten the pharynx, reducing bolus transit time
Contraction also raises the larynx towards the epiglottis, closing the laryngeal inlet
What/where are the constrictor muscles of the pharynx?
Outer, circularly arranged layer
Superior, middle and inferior
Contract sequentially from superior to inferior to push the food bolus inferiorly into the oesophagus
What is the oesophagus?
The inferior continuation of the laryngopharynx
Where is the oesophagus?
Lies posterior to the trachea
What is the structure of the oesophagus?
Muscular tube
Muscle type gradually transitions from skeletal proximally to smooth distally
Lined internally with non keratinised stratified squamous mucosa
